Why not Trump?

Donald Trump is currently leading the race for the Republican presidential nomination. What should conservatives think of this?
THE GOOD Trump has attacked political correctness and skewered some deserving targets, from Jeb Bush to Bill Clinton. He also brought greater prominence to immigration issues and pushed the debate on these issues to the right.
THE ISSUES So where does Trump stand on the issues? With the exceptions of trade and eminent domain, he doesn’t seem to have been consistent on any issue. Most positions have changed over time, and some seem to vary from day to day or even minute to minute.
ABORTION In 1999, Trump said “I’m pro-choice” and refused to support a partial-birth abortion ban, citing his “New York background”. He claims to have become pro-life (with exceptions) a few years ago. He has continued to praise Planned Parenthood for its non-abortion services during the campaign.
GUN RIGHTS Trump once said that “I hate the concept of guns” and supported banning “assault weapons” and waiting periods. During his campaign, he has taken pro-gun positions.
TAXES In 1999, Trump advocated a 6 trillion dollar wealth tax to eliminate the national debt. More recently, he has said the plan was good at the time, but is now impractical. During the campaign, Trump has proposed a tax plan that has mostly been well-received by conservatives.
HEALTH CARE Trump has pledged to “repeal and replace” Obamacare. But replace it with what? Trump has praised socialized medicine in Canada and Scotland in the past. He seems to advocate this for America as well, calling for government to pay for everyone.
RACIAL PREFERENCES One issue where Trump has not taken a politically incorrect position is racial preferences (“affirmative action”). When Antonin Scalia asked a question critical of affirmative action (citing the mismatch theory), Trump criticized Scalia. He went on to declare support for affirmative action.
EMINENT DOMAIN Trump has consistently defended the use of private eminent domain—that is, the government taking someone’s land (with compensation) for a private developer. Trump tried to take the Atlantic City house of elderly widow Vera Coking for a limousine parking lot but lost a court battle. He supports the Kelo Supreme Court case allowing private eminent domain. While this isn’t the most pressing issue (most states have banned private eminent domain) it shows that Trump favors the interests of big business over the rights of average citizens.
IMMIGRATION Trump proposed a great immigration plan, which was apparently written by Senator Jeff Sessions and his staff. However, he has not always advocated for tough immigration policies. In 2012, he opposed Mitt Romney’s support of ‘self-deportation’ (illegals leaving on their own in response to restriction of jobs and benefits), calling it “mean-spirited”, and defended his position in 2015. In 2013, he met with ‘immigrant advocates’ saying that “you’ve convinced me” on the issue. In June 2015, he supported a path to citizenship for illegals. In August 2015, he called for taking in Syrian refugees, before dramatically reversing himself and calling for ending all Muslim immigration.
DONATIONS Trump has donated to a raft of liberal politicians, including Hillary Clinton, Joe Biden, Harry Reid, Chuck Schumer, Ted Kennedy, Jimmy Carter, and many more. Trump excuses this as a business necessity, rather than the product of ideological conviction. Of course, Michigan conservatives have not excused donations to democrats by moderate Republicans like Rick Snyder and Bobby Schostak. At a minimum, Trump’s donations show a willingness to go along to get along, rather than fight a corrupt system.
CHARACTER Trump has been married three times, and had several affairs. He can be gracious to win people over, but will viciously attack those who don’t give him what he wants.
ELECTABILITY Trump has trailed Hillary Clinton in most polls, performing worse against her than Ted Cruz or Marco Rubio. His unfavorable rating is 58% as of this writing, far higher than any candidate who has ever been nominated for president. Liberals are compiling opposition research files on his business dealings, treatment of employees and acquaintances, and controversial statements in past interviews. Barring some game-changing event (such a Clinton indictment or Bloomberg third-party campaign), Trump is likely to lose the general election.
SUMMARY Donald Trump has very little history in the Republican party, much less the conservative movement. He has very recently taken more conservative positions. The question voters must ask is whether there is any reason to believe him. Did he really have a massive political conversion within the past few years, or is he just cynically saying what voters want to hear?

See also:
Is Donald Trump Conservative? Here's the Rundown
Conservative Review on Trump
Club for Growth on Trump